The present invention relates to economically viable uses of residual fuel oil. More specifically, the present invention relates to treating vanadium-containing residual fuel oil such that it can be combusted in a gas turbine to generate power without deleterious effects to the gas turbine from the vanadium.
The high efficiency, low capital cost and short lead time of gas turbine-based systems make them particularly attractive to electric utilities as a means for producing electrical power. However, traditionally, gas turbine operation has been limited to expensive, sometimes geographically scarce, fuels--chiefly distillate oil and natural gas. Unfortunately, gas turbine-based systems do not tolerate fuels containing metals, such as vanadium. When vanadium-containing fuels are burned above 650.degree. C. (1200.degree. F.), as is done in gas turbines, the vanadium attacks the metal components of the turbine and shortens their useful life.
One such vanadium-containing fuel is the residual fuel oil ("RFO") that is a by-product--and is often considered a waste by-product--of the crude oil refining process. Traditional approaches involve either blending the RFO into the fuel oil pool, which will lower the fuel quality, treating the RFO, selling at market demand which may be at a significant loss, or disposing of it. The treatments for the RFO are relatively expensive, using such methods as fluidized bed catalytic cracking, residual oil supercritical extraction, supercritical fluid extraction, high pressure hydrocracking, flexicoking, thermal visbreaking, gasification, delayed coking, centrifuging, and applying magnesium-based vanadium inhibitors in the RFO. The untreated RFO has little open market value, and often the refinery must give it away or pay to have it taken.
With more lower quality crude oil being refined than in the past, the amount of RFO being produced is increasing. Often, the third and second world countries choose to sell their refined oil abroad for much needed capital, rather than consume it internally in gas turbines to generate power. This results in fuel existing in these countries in the form of RFO, without an economically viable way to generate power from it.
It is therefore desirable to provide an economical method and system to generate power from the RFO.